CODEWITHSUNDEEP
knockout.js
user2202911
user2202911

Reputation: 3014

Explicitly change a knockout observable value

I want to explicitly change a knockout observable. I tried doing something like this but what happened was the integer was written to the variable and the observable was over written: 

self.test = ko.observable(); 

var array = [1,3,4]; 

self.test = array.length; //self.test is no longer an observable, is now an int with value of 3

I tried doing something like this too: 

self.numOfAsstsInUpdateGrid() = self.dynamicData.length;

But I get an "Invalid left-hand side in assignment" error

Upvotes: 0

Views: 103

Answers (2)

Stanley Hudson
Stanley Hudson

Reputation: 9

self.test(array.length);

This will preserve test as an observable and set it equal to array.length. Whenever you're setting the value of an observable, you pass the desired value in the parentheses.

Upvotes: 1

Calvin
Calvin

Reputation: 181

If you plan on using an array I'd recommend using ko.observableArray. Which has some nice helper functions like remove. Changing the value of observable can be done by passing a value into the observable function. Like so

self.test = ko.observable();

self.test([1,3,4]);

Calling the function will return the value.

var length = self.test().length;

Upvotes: 0

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